Rosetta Update: The Scent of a Comet

9 November, 2014 / Blog, Slider / By 
An artist's portrayal of the moment when Rosetta's Philae lander touches down on Comet 67P/Churyumov-Gerasimenko.
 ESA / ATG medialab -

Days from now, the Philae lander will drop onto Comet 67P/Churyumov-Gerasimenko. In the meantime, the “mother ship” Rosetta is watching the icy nucleus — and smelling the mix of gases escaping from it.

In less than a week, teams of comet scientists in Europe and elsewhere will witness the culmination of an effort begun by the European Space Agency nearly two decades ago. A small instrumented probe, named Philae, will descend toward the icy nucleus of Comet 67P/Churyumov-Gerasimenko and gently drop onto its surface — becoming the first spacecraft to land on a comet. (Here’s the timetable for the landing on November 11th.) ESA engineers are hoping Philae will operate there for several weeks.

Amid all this drama, however, a second mission is taking place. Rosetta, the washing-machine-size “mother ship”, has been slowly orbiting the comet’s irregularly shaped nucleus since mid-August. It’s been busy for the past 2½ months, not only assessing the terrain for an optimum landing site but also taking stock of the nucleus and its activity.

ESA's Rosetta spacecraft bristles with scientific instruments to study the physical and chemical characteristics of Comet 67P/Churyumov-Gerasimenko. European Space Agency
ESA’s Rosetta spacecraft bristles with scientific instruments to study the physical and chemical characteristics of Comet 67P/Churyumov-Gerasimenko.
European Space Agency

Rosetta’s scientific payload consists of 10 instruments — 11 if you count the craft’s radio transmitter, which plays a crucial role in determining the shape and mass of the nucleus. Public interest to date has focused on OSIRIS, the German-built Optical, Spectroscopic, and Infrared Remote Imaging System. The camera’s two lenses, 140 and 700 mm in focal length, have provided all of the dramatic views seen to date.